Closure device for vacuum tanks



Get. 22, 1940. MQQN CLOSURE DEVICE FOR VACUUM TANKS Original Filed Nov. 1, 1933 Patented Oct. 22, 1940 UNITED STATES CLOSURE DEVICE FOR VACUUM TANKS Alexandra Moon, El Monte, Calif., assignor to Margaret Crosse, Los Angeles, Calif.

Original application November 1, 1933, SerialNo.

Divided and this application December 27, 1937, Serial No. 181,811

4 Claims.

This application is a division of my prior application, Serial No. 696,121, filed November 1, 1933, now matured into Patent No. 2,134,924.

This invention relates to a door for a vacuum tank, and more particularly to a tank in which vacuum sterilizing is carried on.

In vacuum sterilizing extreme evacuation is necessary. It is often necessary to evacuate to 29 inches of mercury and to hold this extreme low pressure for as long as seventy-two hours or more. To accomplish this a door or entrance must be absolutely air-tight and at the same time of great strength to withstand the air-pressure on its outer side. It is, therefore, an object of this invention to provide a door which will not only withstand but which by its peculiar convex inner shape equalize the efiect of outer pressure and inner vacuum in such a Way that there can be no air leakage around the gasket.

An object of this invention is to provide a door that will be air-tight for long periods of time.

In my invention an extremely strong and airtight door has been provided by the use of a double walled door constructed in such a manner as to fully brace both walls. The inner wall is constructed in convex form with its outer edges against the inside of the outer wall. This type of door further permits the door to extend clear across the end of the tank and thus a complete sealing gasket can be placed to extend beyond the ends of the tank. This permits the outer wall to engage and compress the gasket and make an airtight joint.

Other objects and advantages will be apparent from a study of the following specification read in connection with the accompanying drawing, wherein Fig. l is a side view of the end of a vacuum tank showing the door in its closed position.

Fig. 2 is a front view of the door.

Fig. 3 is an enlarged section view of Fig. l.

The treating chamber I is constructed to withstand a high degree of vacuum and for this reason is subject to a high atmospheric pressure;

l therefore, it is necessary that it be strongly built to sustain such pressure. As large articles to be fumigated or sterilized are placed in the chamber I, it is necessary that the entire end be a door. A door 2, necessarily quite large, is provided with substantial supporting means which consist of a swinging crane 3 that is mounted upon and journaled in a pair of bracket arms or hangers 4, which are welded or otherwise secured to the body forming the treating chamber I. The crane 3 is furnished at each each with a laterally extending arm 5, said arms being reinforced by braces 6. The door 2 is of a circular character and the diametrically opposite sides are pivotally connected with the free ends of the arms 5 in order that said door may be swung to and from open position by the crane 3 and may at the same time be pivotally adjusted withrelation to said crane by means of the bolts 1 which extend through arms 5' andengage angle plates 8 that arewelded to and extend from door 2.

In order to clamp the door 2 firmly upon the body member forming the treating chamber and to make sure of an air-tight fit, a gasket 9 and clamping means are provided therefor. The door is furnished with aspider-like arrangement of thrust bars III which are furnished with tapered extremities II. These tapered extremities cooperate with the latch openings I2 in the catch arms I3, which are weldedor otherwise secured to the exterior of the chamber I. E ach catch arm I3 is furnished with a shank portion I4, whereby it is secured to the body forming the chamber and has an outwardlydirected central portion I5, thus causing the end portion of the arm to be ofiset awayvfrom and beyond the periphery of the body member forming the treating chamber I. I

The thrust bars II] are mountedto slide under keepers I6 and I1 carried by and secured to the door 2. In order to force said thrust bars lflinto their operative position, a plurality of thrust and knuckle motion levers I8 are provided, and each of these levers is respectively pivotally connected at I9 with the inner end of its associated thrust bar I0 and at its other end is pivotally connected with an associated lug formed upon a central collar 2|. Within the collar 2| is a shaft which has a screw threaded connection with said collar. Said shaft 22 is provided with a hand wheel 23 by which it.may be. operated. The inner end portion of said shaft projects through the door 2, within which it is provided with a foot portion 24. Said door 2. is provided with a saucer-shaped brace plate 25 to the center portion of the concave side of which. is secured a socket member 26, within which the footportion 24 of the shaft 22 has a working fit. A ball thrust bearing 21 is preferably provided upon the socket member 26 and the foot portion 24 of the shaft. Upon its foot portion and outside of but adjacent to door 2 the shaft 22 is provided with an annular groove 28, and a two-part collar 29 is fitted into said groove and issecured to the door 2 by means of screws 30. Said collar 29 forms an outer bearing for the shaft 22 and with groove 28 prevents endwise movement of shaft 22.

The construction which has just been described afiords a very efficient and substantial means for securing the door 2 in its closed position and for mounting the door for ease of opening and closing the same; Means will next be described whereby an air tight fit is secured between the peripheral portion of the door and the adjacent end of the body member that forms the treating chamber.

Owing to the fact that the extremities of the til catch arms l3 are offset laterally away from the chamber, a space is provided between each of these arms and the end of the chamber l. Within this space it fitted a ring or band 3| which fits snugly within the arms l3 just above theiroutwardly deflected portions l5. To the inner side of ring 3| is welded a narrow ring 32, which in turn is welded to the exterior of the body forming the chamber l. The ring 32 is of less width than the ring 3| and is arranged in such a manner with relation to the ring 3| that when the parts are assembled, as shown in the upper portion of Figure 3, an annular groove 33 is provided around the end of the body member. Within this groove 33 is seated a circular ring or gasket 9 of a compressible character, such as rubber, and this gasket is of sumcient thickness to completely fill the groove and of sufiicient width to project some distance beyond the end of the body member that forms chamber I. When the door 2 is clamped to the body member forming the treating chamber, the action of the tapered end portions ll of bars Ill, being forced into openings 12, will forcibly compress the gasket 9 in order to make an air-tight fit of the door relative to the chamber. The gasket 9 may be supplemented by means of an internal ring 34, also of compressible material, the latter ring being of a sufficient thickness to press firmly upon the peripheral portion of the saucer-shaped plate 25 when the door is clamped into closed position.

There has always been collapse of large vacuum tanks. This door closure prevents collapse because of the convex shape of the inner plate 25 of the door closure and the edge of the tank. It braces the end of the tank in such manner that it prevents collapse of the tank wall as well as of the door. In large tanks a door is placed at each end. It has been shown in practice that in large tanks with a convex shape of the inner plate of the door the pressure is withdrawn more evenly and prevents the collapse of the tank by regulating the pressure. The convex shape of the inner wall 25 at each end of the tank when closed regulates pressure so that it more evenly relieves the tension caused by pressure on the outside.

While I have shown and described a preferred embodiment of my invention I do not desire to limit myself to any of the details of construction shown herein except as defined in the appended claims.

I claim:

1. In a vacuum tank for sterilizing; a tubular body open at one end; a door for closing said open end, comprising a plate having a diameter exceeding that of said body so that when in closed position its edge overlaps said end of the body; catch arms secured on the outer side of said body and having portions with latch openings offset away from and beyond said open end; keepers fixed on the outer side of said plate; bars slidable under the keepers to engage or disengage said arms within said openings; rings between the catch arms and said body arranged to form an annular groove; a gasket in said groove extending beyond said open body end so as to be compressed by said plate when the bars engage within said arms; and means on the door for actuating all of said bars comprising a shaft rotatable in the door, a collar threaded on the shaft, and levers one for each of the bars, pivoted at one end to the collar and at the other end to the adjacent end of the respective bar.

2. In a vacuum tank for sterilizing; a tubular body open at one end; a door for closing said open end, comprising a plate; catch arms secured on the outer side of said body; keepers fixed on the outer side of said plate; a compressible gasket on the outer side of said body projecting beyond the open end thereof; bars slidable under the keepers to engage or disengage said arms and when engaged therewith to force said plate against said gasket; a shaft rotatable in the door; a collar threaded on the shaft; and levers one for each of the bars, pivoted at one end to the collar and at the other end to the adjacent end of the respective bar, whereby upon rotation of the pivot in one direction or the other the collar will be moved axially of the shaft to move said levers axially and thereby axially move said bars to engage or disengage the catch arms according as the shaft is rotated in one direction or the other.

3. In a vacuum tank for sterilizing; a tubular body open at one end; a door for closing said open end, comprising, an outer flat plate and an inner plate of dished form, the outer plate having a diameter exceeding that of said body and said inner plate so that when the door is in closed position the edge of the outer plate overlaps said end of the body; catch arms secured on the outer side of said body and having portions with latch openings offset away from and beyond said open end; keepers fixed on the outer side of the outer plate; bars slidable under the keepers and having outer ends engageable within said openings and tapered to force the outer plate toward said body; a gasket secured on the outer side of said body beneath said .catch arms and projecting beyond the open end of said body; a compressible ring between the open end of said body and the perimeter of the inner plate; and means on the door for actuating said bars to cause their ends to engage said arms, whereby the gasket and ring will be compressed and the ring pressed against the perimeter of the inner plate.

4. In a vacuum tank for sterilizing; a tubular body open at one end; a door for closing said open end, comprising, an outer flat plate and an inner plate of dished form, the outer plate having a diameter exceeding that of said body and said inner plate so that when the door is in closed position the edge of the outer plate overlaps said end of the body; catch arms secured on the outer side of said body and having portions with latch openings offset away from and beyond said open end; keepers fixed on the outer side of the outer plate; bars slidable under the keepers and having outer ends engageable within said openings and tapered to force the outer plate toward said body; a gasket secured on the outer side of said body beneath said catch arms and projecting beyond the open end of said body; a compressible ring between the open end of said body and the perimeter of the inner plate; and means on the door for actuating said bars to cause their ends to engage said arms, whereby the gasket and ring will be compressed and the ring pressed against the perimeter of the inner plate, said means comprising a shaft extending through and rotatable in the outer plate, a socket member secured to the inner plate and in which the inner end of said shaft is rotatably received, a collar threaded on the shaft, and levers one for each of the bars pivoted at one end to the collar and at the other end to the adjacent end of the respective bar.

ALEXANDRA MOON. 

